266 Rimlerpest 
Method. The blood is diluted with a mixture containing 1 "/o of 
citrate of potash, and 0'5 “/o of ordinary medicinal methylene blue. 
Different proportions of the fluid miist be added, varying from one-fifth 
to one-third of the volume of blood, according to the condition of the 
latter, which as taken from the vein may be almost tarry, or excessively 
hydraemic. 
Of the mixture, some specimens are put up under cover-glasses, 
sealed at the edges with a paraffin of low melting-point; other portions 
are put in watch-glasses, exposed to the air, but not to light, and are 
kept in Petri dishes arranged as moist-chambers. When examination 
reveals the presence of the specific bodies in these preparations, films 
may be spread in the ordinary way, and fixed as permanent specimens. 
Appearances. 
Forms seen: 
(a) After an uncertain period, from 6 to 48 hours, there appears 
upon the blood corpuscle a blue point or dot; later there becomes 
evident an extension from the dot, in the form of one or more delicate 
streaks or fine lines going deeper into the corpuscle. Ultimately, by 
extending and thickening, the lines usually demarcate a long, fine, 
needle- or sword-shaped body, which may extend into, or across, or even 
through the corpuscle, projecting from it at either or both of its 
extremities. 
The body may be straight or curved; it may present a single or 
double contour. Its breadth varies within wide limits. The ends may 
be pointed or oval. It may lie all in one plane, or be obviously twisted; 
sometimes it is acutely bent, or even folded double. In perhaps the 
greater number of instances it lies curved and closely pressed into the 
periphery of the corpuscle, and in these cases its aspect is such that 
it might be taken for a mere overstaining of the edge of the erythrocyte. 
Where the bodies protrude through the wall of the corpuscle they often 
emerge freely, but in other cases they may carry the membrane with 
them, causing the coi’puscle to become elongated and assume the shape 
of a fish, or a float. The extreme ends of the bodies when free are 
sometimes blunt and rounded, but at others extremely tenuous. In 
length they may exceed two or three times the diameter of the disc. 
Broader forms occur, often crumpled or folded so as to show two or three 
ridges or lines of stain. When seen on the flat the edges are extremely 
faint 
